Lecture 18: Vertebral Column and Back Musculature Flashcards
2 divisions of skeleton
-axial
-appendicular
axial skeleton: 4 components
-skull/cranium
-vertebral column
-ribs
-sternum
appendicular skeleton: 4 parts
-limb bones
-pelvis
-scapula
-clavicle
what are joints (2 functions)
articulations that:
-firmly unite bones
-allow specific movements between bones (restrict unwanted movements)
flexion: definition
movement that reduces angle between bones
extension: definition
movement that increases angle between bones
lateral flexion
flexed to the right
extended to the left
dorsiflexion/dorsoventral flexion: definition
-bending toward body
dorsiflexion in cheetah significance
increases stride length
5 functional regions of vertebral column
-cervical
-thoracic
-lumbar
-sacral
-coccygeal
cervical vertebrae: appearance
-small spinous process
-transverse process splits into dorsal and ventral tubercles
thoracic vertebrae: appearance, articulation
-prominent spinous process
-short transverse process
-articulate with ribs
lumbar vertebrae: appearance, articulation
-transverse process cranioventrally oriented
-blunt spinous process
-articular processes in sagittal plane
coccygeal vertebrae
3-5 fused vertebrae
-articulate with ileum at sacroiliac joint
number of vertebrae: canine
C7, T13, L7, S3, Cd20
**Cd = caudal/coccygeal
number of vertebrae: equine
C7, T18, L6, S5, Cd20
number of vertebrae: bovine
C7, T13, L6, S5, Cd18-20
number of vertebrae: caprine (goat)
C7, T13, L6-7, S5, Cd16-18
number of vertebrae: porcine (pig)
C7, T14-15, L6, S4, Cd20-23
what 2 regions of vertebral column are variations between species most prominent
thoracic and caudal
vertebrae articulate via _________ and ______________
ligaments, joints
intervertebral discs: location and functions
-between vertebral bodies
-compressible, absorb shock, allow movements along many axes
function of synovial joints
-joint capsules
allow sliding movements between articular processes (arches) of adjacent vertebrae
what do synovial joints contain
synovial fluid (smooth, viscous lubricant)
2 components of intervertebral disk
-anulus fibrosus
-nucleus pulposus
nucleus pulposus
-central core of intervertebral disk
-semifluid at birth but dehydrates with age
anulus fibrosus
-concentric rings of fibrocartilage surrounding nucleus pulposus
function of joints
allow stereotypic, predictable movement
function of ligaments
limit excessive movement across joints
4 vertebral ligaments
-supraspinous
-interspinous
-dorsal longitudinal
-ventral longitudinal
supraspinous ligament: 2 functions
-connect spinous processes of vertebra
-limit excessive flexion of vertebral column
interspinous ligament: 2 functions
-connect spinous processes of vertebra
-limit excessive FLEXION of vertebral column
supraspinous vs interspinous ligament location
supraspinous = superficial
interspinous = deep
which vertebral ligament(s) do cats lack
supraspinous and nuchal
3 functions of dorsal and ventral longitudinal ligaments
-connect vertebral bodies
-limit disc herniation
-limit extension EXTENSION
which ligament is a specialized part of the supraspinous ligament
nuchal ligament
supraspinous ligament continues into the neck as __________
nuchal ligament
nuchal ligament functions (2)
-support majority of mass of the head without muscular effort
-where muscle attaches
where does nuchal ligament attach to (which vertebrae)
C2
vertebral foramen definition
hole of vertebrae (where spinal nerves form and branch)
ramus is latin for
branch
spinal nerve roots: function and 2 types
-dorsal and ventral
-join to form spinal nerve then branch into rami
dorsal root branches into
dorsal rami
ventral root branches into
ventral rami
which direction does dorsal rami travel
dorsally
dorsal vs ventral rami size
ventral are larger
spinal nerve communicans
-white and grey
-branch of ventral rami
-sympathetic trunk ganglion (pathway for ANS)
dorsal root ganglion: neuron type
sensory, pseudounipolar
epaxial muscles function
-support vertebral column
-major part of locomotion
which ramus innervates epaxial muscles
dorsal
dorsal root ganglion function
contain cell bodies for dorsal roots
do epaxial muscles attach to limbs
no
what kind of movements do epaxial muscles produce (hint: think anatomical planes)
sagittal
origin: definition
proximal end of muscle that is fixed during contraction
insertion: definition
distal end of muscle that attaches to mobile portion of bone
innervation: definition
peripheral nerve that provides motor innervation to and takes sensory innervation from a muscle
action: definition
product of movement generated by muscle contraction
hypaxial muscles are innervated by which rami
ventral
ventral rami innervate what structures
-hypaxial muscles of back
-all other somatic structures of body
cutaneous trunci: OINA
O+I: skin and superficial fascia of dorsal, lateral and ventral walls of thorax; abdomen
N: lateral thoracic nerve
A: twitches skin
function of hypaxial muscles
-limb movement and stability (locomotion)
where are hypaxial muscles positioned relative to expaxial
superficial to epaxial
if the muscle attaches to a limb, is it hypaxial or expaxial
hypaxial
trapezius: OINA
O: meidal raphe and supraspinous ligament from C3 to T9 vertebrae, nuchal plane of skull
I: spine of scapula
N: vagus nerve
A: elevation of limb, draws it forward
latissimus dorsi: OINA
O: lumbosacral fascia from spinous process of L vertebrae and last thoracic vertebrae, arises from last two or three ribs
I: teres tubercle and greater tubercle of humerus
N: pectoralis caudales and thoracodorsalis
A: draw limb forward and laterally, support limb, draw limb against trunk, draw limb backward during flexion of shoulder, decelerates forward motion of limb
3 epaxial muscle groups/systems
-longissimus
-iliocostalis
-transversospinalis
epaxial muscle systems/groups AKA
errector spinae
joint action of epaxial muscles
extend vertebral column
iliocoastaliis location
-ventral to other epaxial muscles
-from pelvis to blade of ribs
3 muscles in transversopinalis system
-spinalis (capitis, cervicis)
-semispinalis (capitis, cervicis)
-multifidus
semispinalis cervicis: OINA
O: spinous processes of first 3 thoracic vertebrae, nuchal ligament
I: nuchal crest and mastoid process
N: dorsal rami of spinal nerves
A: extend neck and head, assist in turning neck laterally
what is the most superficial epaxial muscle in the cervical region
semispinalis cervicis
spinalis vs semispinalis vs multifundus location
semispinalis = most cranial
spinalis = caudal
multifundus = caudal to semispinalis
longissimus: location and attachements
-between iliocostalis and transversospinalis
-insert craniolaterally
3 muscles for longissimus (based on location)
-cervicis
-thoracis
-lumborum
bilateral contraction of epaxial muscles causes what action
extension
unilateral contraction of epaxial muscles produces what action
flexion
2 muscles of iliocostalis (based on region)
thoracis, lumborum
thoracolumbar fascia functions
-deep, dense fascia
-gives attachment to multiple muscle groups
-provide stability and support to caudal lumbar region
splenius
extends from T3 to skull
